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ispartof: HEMASPHERE vol:3 issue:2 ispartof: location:United States status: published

The idiopathic hypereosinophilic syndrome (HES) comprises a heterogenous group of disorders characterized by marked blood eosinophilia with eosinophilia-associated organ damage. Eight patients with a median age at diagnosis of 42 years (range 19-67) received imatinib mesylate (IM) for FIP1L1-PDGFRα-negative HES resistant to previous conventional treatment. Median number of prior therapies was 3 (range 2-4). Median time from diagnosis to IM initiation was 112 months (range 2-293). Four patients were treated daily with 100 mg IM, whereas the remaining four patients were treated daily with 400 mg IM. Four male patients (50%) achieved complete haematologic response (CHR) after median of 7 days (range 3-150) using 100 mg daily IM (n = 2) and 400 mg (n = 2). Median duration of IM treatment for IM responders was 18 months (range 2-88). No adverse events were reported throughout the treatment duration. Two patients maintained CHR while on 100 mg weekly IM. Four patients (2 men and 2 women) failed IM treatment. Median duration of IM for non-responding patients was 3 weeks (range 3-12). Non-responding HES patients were significantly older and had lower percentage of blood eosinophilia when compared with IM responders. Our results suggest that IM, even at lower than conventional doses, may induce and maintain long-term remission for FIP1L1-PDGFRα-negative HES.

Presence of the oncogenic mutation FIP1L1-PDGFRalpha in hypereosinophilic patients is predictive of hematologic response to imatinib mesylate. However, most patients with hypereosinophilic syndrome (HES) do not have this mutation and have not responded to imatinib doses traditionally successful in patients who test positive for FIP1L1-PDGFRalpha. A patient with FIP1L1-PDGFRalpha-negative HES who had intolerance of interferon alpha-2b and hydroxyurea was treated with escalating doses of imatinib. At 800 mg of imatinib daily, eosinophilia was controlled, allowing prednisone tapering and control of clinical and laboratory-detected abnormalities. HES patients who test negative for FIP1L1-PDGFRalpha may benefit from a trial of higher-dose imatinib.

Imatinib is the treatment of choice for FIP1L1-PDGFRalpha (F/P+) positive myeloproliferative neoplasms, but little is known about optimal dose and duration of treatment to maintain complete molecular remission once achieved. We describe a case of F/P+ patients who started imatinib and reached a molecular remission, but did relapse after 15 months of therapy for poor adherence to therapy, and re-obtained remission only with standard dose of 400 mg/day. We reviewed the literature and highlights the need of quantitative molecular procedures to modulate imatinib dose.

A 55-year-old man was referred to our dermatology department with a 5-month history of nasal bleeding, crusted erosions on the lips (figure 1) and painful oral mucosal ulcerations unresponsive to systemic acyclovir therapy prescribed by a family physician. He was unable to swallow due to agonising pain, and lost 20 kg. The patient was initially suspected of paraneoplastic pemphigus (PNP). Histological examination of the lip and oral mucosa showed non-specific mixed cellular infiltrates without predominance …